Put more accuracy on top of your firearm without having to put more into it. The Holosun HS403B Micro Reflex Sight employs advanced LED technology that squeezes up to 5 years of life from a single battery and is 4x more efficient at the highest brightness setting. Shake Awake motion-sensing feature powers up the optic with the slightest movement. Multi-coated lens offer a parallax-free sight picture with unlimited eye relief. Durable 6061-T6 aluminum construction is unaffected by extreme weather conditions and a 1/3 co-Witness and low mount are both included.